Subterranean drilling systems that employ downhole drilling motors are commonly used for drilling boreholes in the earth for oil and gas exploration. Subterranean drilling systems typically include a housing enclosing a downhole drilling motor operably connected to an output shaft. One or more thrust-bearing apparatuses may also be operably coupled to the downhole drilling motor for carrying thrust loads generated during drilling operations. A rotary drill bit may also be connected to the output shaft and be configured to engage a subterranean formation and drill a borehole.
Each bearing apparatus may include a stator that does not rotate and a rotor that is attached to the output shaft and rotates with the output shaft. The stator and rotor may each include a plurality of superhard bearing elements or inserts. Each superhard bearing element may be fabricated from a polycrystalline diamond compact (“PDC”) that provides a bearing surface that bears against other bearing surfaces during use.
In a conventional PDC bearing apparatus, a bearing assembly may include a support ring that may be configured to accept a number of superhard bearing elements. The superhard bearing elements may be made from a polycrystalline diamond layer formed on a cemented tungsten carbide substrate. These superhard bearing elements are commonly manufactured by machining cylindrical PDCs. The manufacture of superhard bearing elements from PDCs traditionally requires complex and repetitive cutting and/or grinding, making the manufacturing process expensive and time consuming. Moreover, common manufacturing processes produce a single superhard bearing element per PDC, wasting a significant portion of the PDC and ultimately increasing the cost of superhard bearing elements for users.
Therefore, manufacturers and users of bearing apparatuses continue to seek improved bearing apparatus designs and manufacturing techniques.